LARGEST TELESCOPE

Poverty Bay Herald, Volume LXI, Issue 18590, 28 December 1934, Page 3

LARGEST TELESCOPE

HUGE MIRROR CAST

20-TON DISC

LONDON, Nov. 9.

The biggest telescope in the world is the lOOin. reflector at the Solar Physics Observatory on Mount Wilson, California, and when it was erected some years ago, few people believed that a bigger one could be made, owing to the huge expense and the extreme difficulty of casting and accurately grinding to tho eight curvature glass discs exceeding iOO inches in diameter. But tho enorrnOUs extent of tho universt! disclosed by the lOOin. telescope suggested that still, more marvels' of; space would he revealed could a still larger telescope he constructed, and tho International Education Board agreed to finance any feasible project for making a still larger instrument. So some years ago a committee of American astronomers, assisted by English and German astronomers, set to work and drew up plans for a reflecting telescope with a mirror 2Qoin, in diameter, and last week it was announced (hat Ihe Corning Glass Works, of New York, had successfully cast a glass disc of that huge size arid weighing 20 tons.

If had been in the mould since April, and a second disc, the same size, is about to be cast in case die first should develop any defects which would render it. unsuitable for the giant telescope.

NEW OBSERVATORY NECESSARY It will bo necessary to build a new observatory on one of the peaks of the Rocky Mountains, near Mount Wilson, to house the telescope, and the' total cost, including the heavy mountings and electrical controlling equipment, is estimated to exceed £1,000,000.

The delicate task of grinding tho mirror when ,sufficiently cool will bo a long and tedious process, us it must be ground

to a paraboloid surface accurate to tho one 500,000 th of an inch. But the experts are confident the mirror will be successfully, completed and place in the hands of American astronomers a telescope with four times the light girasp of the lOOin. instrument, able to photograph objects so far sunk in space that their light, travelling at 186,000 miles a second, occupies hundreds of millions of years in reaching the earth. Something like 1,500,000,000 stars are within photographic range of the lOOin. reflector, and it is expected that this number will be increased to 2,000,000,000 when the new giant is in use.

It will perhaps solve the problem of the Martians and their stupendous system of canals and the still more important problems of stellar evolution and the constitution of matter. The atmospheric conditions in California are ideal for big telescopes, and we in this country have in the 36in. telescope at Greenwich probably the biggest that can be effectively used here/ where £1.000,000 spent on a 200 in. telescope would be money wasted.